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// 定义路径映射
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const PATH_MAP = {
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  "/gravatar": "https://secure.gravatar.com",
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};
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async function handleRequest(request) {
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  const url = new URL(request.url);
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  const pathParts = url.pathname.split('/');
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  const route = `/${pathParts[1]}`;
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  const originBase = PATH_MAP[route];
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  if (!originBase) {
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    // 如果请求的路径不在映射表中，返回 404
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    return new Response('Route not mapped', { status: 404 });
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  }
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  // 构建 cacheKey 和 originUrl
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  const cacheKey = `${route}${url.pathname.replace(route, '')}`;
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  const originUrl = `${originBase}${url.pathname.replace(route, '')}`;
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  // 从 KV 中检查缓存
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  const cache = await REVERSE_CACHE.get(cacheKey, { type: 'arrayBuffer' });
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  if (cache) {
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    // 返回缓存的响应
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    return new Response(cache, {
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      headers: {
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        'Content-Type': 'application/octet-stream',
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        'X-Worker-Cache': 'HIT'
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      }
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    });
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  }
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  // 如果缓存中没有，则从 origin 获取
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  const response = await fetch(originUrl);
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  if (response.ok) {
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    const contentType = response.headers.get('Content-Type');
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    // 检查是否为常见图片类型
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    if (contentType && (contentType.includes('image/jpeg') || contentType.includes('image/png') || contentType.includes('image/gif'))) {
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      const responseData = await response.arrayBuffer();
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      // 缓存响应
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      await REVERSE_CACHE.put(cacheKey, responseData, { expirationTtl: 86400 }); // 缓存一天
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      return new Response(responseData, {
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        headers: {
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          'Content-Type': contentType,
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          'X-Worker-Cache': 'MISS'
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        }
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      });
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    } else {
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      // 不是常见图片类型，不缓存，直接返回
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      return response;
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    }
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  } else {
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    return new Response('Not found', { status: 404 });
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  }
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}
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addEventListener('fetch', event => {
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  event.respondWith(handleRequest(event.request));
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});